Network backup methods typically utilize file image backups and/or volume image backups. File backups backup individual files, while, a volume backup backs up all data in a specified volume. Block based backups (BBB) bypass the file system and read data directly form the disk or volume, and can either read data in the same sized blocks as the file system or in different sized blocks.
Backup systems in present enterprise deployments are under increasing pressure to meet the various service level agreement (SLA) terms that the backup vendor to do more with fewer resources, optimize the cost models, and honor ever aggressive backup SLA and SLO (service level objective) terms, such as improve TCE (total cost of entry) and reduce TCO (total cost of ownership). Recent developments have led to great improvements in the way backup is done and have cut down backup windows as well as reduced the total cost of ownership. Block based backups are one such development. In a BBB system, the backup process copies blocks of data and then all the differential backups also are taken by copying only the new blocks from last backups. This brings a lot of efficiency in the way backups are taken. Another development is that of dynamic parallel save streams (DPSS). This feature increases net aggregate backup throughput written to the backend media. It splits the data save set into multiple save streams and backs up the data in parallel. DPSS allows the streams vacated from one savepoint to be reclaimed by another. This approach allows full utilization of all available save streams at any given time regardless the number of savepoints specified for the backup or how many streams each save point has started with in the beginning.
In general, traditional backups are less efficient when there are more blocks but less of a file system/folder structure available. Backup techniques like incremental/differential and synthetic full backups (forever incremental) are not fully realized in such cases either. Thus, present backup techniques are generally limited in scope to few workflows and configurations only. Parallel save set (PSS) technology is promising with respect to increasing backup efficiency, however it is only implemented at the file level. What is required, therefore, is a backup solution that implements DPSS at the block level to obtain fully optimized block level backups.
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